天安门广场油松2010年春季死亡原因及技术措施

为探究天安门广场油松在2010年春季针叶枯黄并逐渐出现大规模死亡的原因，对油松外部形态及根部特征进行了调查分析；对油松所在土壤理化性质进行了化验分析及立地条件调查分析；结果表明：大部分油松整株针叶枯黄，毛细根萎缩干瘪，菌根腐烂死亡；油松表层土壤中盐分含量过高，根系吸收大量盐分并失去吸收水分和养分的功能，导致油松针叶出现枯黄最终整株死亡；油松生长空间狭小、土壤密实度高，土壤通风透气性差、热辐射增加等方面因素不利于油松正常生长。2009年冬季雪后天安门广场油松周边施撒大量融雪剂是造成油松死亡的直接原因，为保护绿化成果和景观效果，对预防融雪剂危害及不良立地条件现状，提出相应的技术措施和建议。

Death Causes of Chinese pine (Pimus tabulaeformis) at the Tiananmen Square in Spring 2010 and Technical Measures

In order to explore some causes why pine needles turned yellow and many Chinese pine trees gradually died at Tiananmen Square in Beijing, China in spring 2010, a field investigation was conducted on the external morphology and the root characteristics of Chinese pine, and meanwhile soil physical and chemical properties and site conditions were also investigated and analyzed. It is found that for most of Chinese pines trees, the pine needles of their whole plants turned yellow, their fine roots withered and shriveled, and mycorhiza were rotten and died. The high salt content was found in surface soils, and the roots absorbed the large amounts of salts and lost the function of absorbing water and nutrients, which led to the emergence of yellow pine needles and the death of the whole plant. Some factors （such as small growth space, high soil density, poor soil ventilation and heat radiation） were not in favour of normal growth of Chinese pine. Moreover, a great amount of snow-melting agent was applied around Chinese pine at the Tiananmen Square after snow in winter 2009, which was a direct cause leading to the death of Chinese pine. In order to protect the achievement in afforestation and visual effects, the corresponding technical measures and suggestions were presented to prevent the hazards of snow-melting agent and to overcome the current status of adverse site conditions.